sedimentary

Conglomeratic gravel / polymictic breccia

Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies

AI-generated identification · may be incorrect

A coarse, poorly sorted aggregate of rounded to angular pebble-sized clasts in a sandy-gray matrix. Visible fragments include quartz, feldspar, dark mafic rocks, and a conspicuous translucent green piece that may be glass or green mineral; individual clasts are generally Mohs 5–7 with variable luster and cleavage.

Identified September 4, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by mechanical weathering, transport, and deposition in a stream, beach, alluvial fan, or gravel fill; clast ages may range from ancient to modern, while the deposit itself may be unconsolidated and geologically young. If cemented, it would be classified as conglomerate or breccia.

Uses & applications

Used as construction aggregate, road base, concrete ballast, landscaping gravel, and occasionally as a decorative stone. This loose mixed material has negligible jewelry or collector value.

Geological facts

The specimen is not a single mineral or uniform rock, so no precise mineral formula or age can be assigned. The bright green fragment should be tested separately before identification.

Field identification & locations

Identify by examining clast roundness, sorting, matrix, and testing representative pieces for hardness, streak, magnetism, and acid reaction. Common in riverbeds, beaches, glacial deposits, quarry products, and artificial fill.